Protesters rally in front of the White House during a protest over the death of George Floyd in Washington D.C., the United States, on May 31, 2020. Protests over the death of George Floyd, an unarmed black man killed in Minneapolis police custody, continued in cities across the United States. (Xinhua/Liu Jie)

President Trump threatened use of military force on Monday to "stop the violence and restore security and safety in America".

Trump said he has "strongly recommended" to every governor to deploy the National Guard in "sufficient numbers that we dominate the streets."

He said mayors and governors must establish an "overwhelming law enforcement presence until the violence has been quelled." If the city or state refuses to take the actions, Trump said he would deploy the US military.

"I will deploy the United States military and quickly solve the problem for them. I am also taking swift and decisive action to protect our great capitol, Washington, DC. What happened in this city last night was a total disgrace," he said.

He added: "Those who threaten innocent life and property will be arrested, detained and prosecuted to the fullest extent of the law. I want the organizers of this terror to be on notice that you will face severe criminal penalties and lengthy sentences in jail."